Sh2-188 is a planetary nebula in the constellation Cassiopeia.
Although included in the Sharpless Catalog, it is actually a planetary nebula, located 711 light-years away from the Solar System.
It appears as a well-marked envelope on one side and very dispersed on the other, where it appears to have already dissolved.
Through its speed of expansion an age of about 7500 years has been determined. Although its appearance resembles a supernova remnant, this possibility has been ruled out due to the nature of its emissions.
(info from Wikipedia)
Optic GSO RC12 Truss - Aperture 304mm, focal lenght 2432mm, f/8
Mount 10Micron GM2000 HPSII
Camera Moravian G3-16200 with external filter wheel 7 positions
Filters Astrodon 50mm RGB filters and narrowband Ha 5nm/OIII 5nm
Guiding system OAG Moravian M68 with guide camera Moravian G1-0301
Exposure details Ha 24x900" bin2 -25C
OIII 17x900" bin2 -25C
RGB 6x600" bin2 -25 for each filter
Total integration 13h15'
Acquisition Voyager, PHD2
Processing Pixinsight 1.8, Photoshop CS5, StarXTerminator, NoiseXTerminator, BlurXTerminator
Location Promiod (Aosta Valley, Italy), own remote observatory
Date 14/16 October, 6/7 November 2021